Improvement of ablative margins by the intraoperative use of CEUS-CT/MR image fusion in hepatocellular carcinoma

Abstract

BackgroundTo assess whether intraoperative use of contrast-enhanced ultrasound (CEUS)-CT/MR image fusion can accurately evaluate ablative margin (AM) and guide supplementary ablation to improve AM after hepatocellular carcinoma (HCC) ablation.MethodsNinety-eight patients with 126 HCCs designated to undergo thermal ablation treatment were enrolled in this prospective study. CEUS-CT/MR image fusion was performed intraoperatively to evaluate whether 5-mm AM was covered by the ablative area. If possible, supplementary ablation was applied at the site of inadequate AM. The CEUS image quality, the time used for CEUS-CT/MR image fusion and the success rate of image fusion were recorded. Local tumor progression (LTP) was observed during follow-up. Clinical factors including AM were examined to identify risk factors for LTP.ResultsThe success rate of image fusion was 96.2 % (126/131), and the duration required for image fusion was 4.9 ± 2.0 (3–13) min. The CEUS image quality was good in 36.1 % (53/147) and medium in 63.9 % (94/147) of the cases. By supplementary ablation, 21.8 % (12/55) of lesions with inadequate AMs became adequate AMs. During follow-up, there were 5 LTPs in lesions with inadequate AMs and 1 LTP in lesions with adequate AMs. Multivariate analysis showed that AM was the only independent risk factor for LTP (hazard ratio, 9.167; 95 % confidence interval, 1.070–78.571; p = 0.043).ConclusionCEUS-CT/MR image fusion is feasible for intraoperative use and can serve as an accurate method to evaluate AMs and guide supplementary ablation to lower inadequate AMs.

Evaluation of the ablation margin of hepatocellular carcinoma using CEUS-CT/MR image fusion in a phantom model and in patients

“…The method of CEUS- CT/MR image fusion used in this study had been reported in our former article [18]. The CT/MR image series in DICOM format were transferred into the navigation system and 3D image volume was generated.…”

“…The term “ablative margin” refers to the 0.5 to 1.0-cm-wide region of normal tissue around the tumor that should ideally be removed during tumor ablation [16, 17]. Therefore, AM is one of the most important factors for the prediction of LTP in HCC patients after RFA [18–20]. However, regular medical imaging methods, including CT, MR, and contrast-enhanced ultrasound (CEUS), are not able to accurately evaluate AM because the tumor and surrounding normal liver tissue mix and merge in the ablative area, and the boundary between normal tissue and the ablative area is difficult to identify.…”

“…In recent years, novel medical imaging methods have been explored to assess AM in HCC patients after ablation, including CT-CT image fusion [21, 22], MR-MR image fusion [23, 24], contrast-enhanced ultrasound (CEUS)-CT/MR image fusion [18, 25], MR with impaired clearance of ferucarbotran [26, 27], and MR with gadolinium ethoxybenzyl diethylene triamine pentaacetic acid [28]. Our group has reported that CEUS-CT/MR image fusion, which can be applied intraoperatively, is useful for assessing AM in HCC patients receiving ablation [25].…”

Comparison of CT/MRI-CEUS and US-CEUS fusion imaging techniques in the assessment of the thermal ablation of liver tumors

“…Several studies have reported on the application of fusion imaging between CT/ MRI and US (CT/MRI-US fusion imaging) for the detection, guidance and evaluation during liver cancer thermal ablation [13][14][15][16][17][18][19][20]. Our previous studies [16,21,22] have also demonstrated that CT/MRI-CEUS fusion imaging is a feasible and accurate method for immediately assessing the treatment response of thermal ablation. The target tumor and 5-mm ablative margin can be depicted in preprocedural CT/MRI images; by overlapping these images with real-time CEUS, operators can intuitively determine whether the target tumor and its ablative margin can be encompassed by the avascular zone.…”

Immediate evaluation and guidance of liver cancer thermal ablation by three-dimensional ultrasound/contrast-enhanced ultrasound fusion imaging

“…We have successfully reported the application of contrastenhanced US (CEUS)-CT/MRI fusion imaging for determining AM after the radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC). CEUS-CT/MRI fusion imaging is helpful in the guidance and assessment of the RFA procedure [10,11]. However, our previous experience has shown that US-CT/MRI fusion imaging is not sufficiently convenient during the ablation procedure.…”